Electron discharge device



Dec. 1, 1936'. p Alco 2,062,892

ELECTRON DISCHARGE DEVICE Filed Dec. 29, 1934 2 Sheets-Sheet l INVENTORJ. R LA/CO V Malta, 6?. 7 ATTORNEY Dec. 1, 1936. J p LA|Q 2,062,892

ELECTRON DISCHARGE DEVICE Filed Dec. 29, 1934 2 Sheets-Sheet 2 INVENTORJ. I? LA/CO AT TORNE V Patented Dec. 1, 1936 ELECTRON DISCHARGE DEVICEJoseph P. Laico, Brooklyn, N. Y., assignor to Bell TelephoneLaboratories,

Incorporated, New

York, N. Y., a corporation of New York Application December 29, 1934,Serial No. 759,683

8 Claims.

Another object of this invention is to maintain an electrode in electrondischarge devices in a desired space relation with another electrode.

In one illustrative embodiment of this invention, an electron dischargedevice, which may be of the general type disclosed in the pendingapplication, Serial No. 750,287, filed October 2'7, 1934, .of.Arthur'LflSamuel, comprises an enclosing vessel and aplurality ofelectrode units within the enclosing vessel. Each ofthe electrode unitsmay comprise a cathode, a control electrode, an anode, and a shieldelectrode and a suppressor electrode between the control electrode andanode. The shield electrodes .are mounted upon a disc or plate and thesuppressor electrodes are mountedupon another disc or plate disposed inproximityto the first plate or discand forming a condenser therewith.The two discs or plates may be secured in proper relation to each otherprior to the mounting thereof within the enclosing vessel, thesuppressor electrodes being mounted upon the disc or plate thereforprior to the securing together of the plates or discs.

In accordance with a feature of this invention, the shield electrodesare individually mounted on supports or plates adapted to be disposedwithin apertures in the shield electrode plate or disc, the supports orplates being secured to the latter plate or disc by a plurality offlexible brackets. The shield electrodes may be accurately positionedwith respect to the corresponding suppressor electrodes by flexing thebrackets.

In accordance with another feature of this invention, the cathodes ofthe electrode units are supported separately from the plates or discscarrying the shield and suppressor electrodes so that expansion andcontraction of the plates or discs will not afiect the positioning ofthe cathodes rel- ;ative to the corresponding control electrodes andanodes.

.The inventionand the features thereof will be understood more clearlyand fully from the following detailed description with reference to theaccompanying drawings in which:

"Fig. 1 is a perspective view'of an electron discharge deviceillustrative of one embodiment of this invention, portions of theenclosing vessel being broken away to show the electrodes more clearly;

Fig. 2 is a plan view of the electron discharge device shown in Fig. 1;

Fig. 3 is a side view in cross-section along line 3-3 of Fig. 2 of thedevice shown in Figs. 1 and 2;

Fig. 4 is a view in cross-section along line 4-4 of Fig. 3 showing theconfiguration and relative disposition of the electrodes; and

Fig. 5 is a partly exploded view in perspective of the shield andsuppressor grid assemblies for the electrode units.

Referring now to the drawings, the electron discharge device showntherein comprises an enclosing vessel having a cylindrical portion l andsubstantially plane end walls I l and I2. Enclosed within the vessel aretwo electrode units, each of which includes a cathode l 9, an anode [4,a control electrode l between the cathode and the anode, and a shieldelectrode or grid and a suppressor electrode or grid disposed betweenthe control electrode and the anode. The electrodes in each unitpreferably are coaxially arranged as shown in Fig. 4 and the two unitsmay be disposed parallel to each other. Preferably the electrodes ineach unit are disposed as-closely adjacent'as is mechanically andelectrically feasible in order that the electron transit times will besmall and the device may be utilized at ultrahigh frequencies.

Each cathode comprises a linear filament l9, which may be of thoriatedtungsten, supported at one end by a flexible J -shaped member or .wire20 extending from a rigid metallic support or rod 2| sealed in the endwall l2 of the enclosing vessel and at the other end by flexible bentwires 22 individually secured to rigid supports or rods 23 also sealedin the end wall I2.

The anode M of each electrode unit includes two sections each having anarcuate portion 24 and a large surface flange 25. The flanges aresecured together in face to face :relation by integral bent tabs 26 onone flange extending through apertures 21 in the other flange so thatthe arcuate portions 24 form, a semi-cylinder which is coaxiallydisposed about the corresponding cathode l9. Each anode is supported bya rigid metallic rod or wire 28 secured to the flanges 25 and sealed inthe end wall ll of the enclosing vessel.

Each of the control electrodes l5 comprises two large area plates 29secured together in face to face relation by integral bent tabs 30 onone plate extending through apertures 3| on the other plate,

the plates carrying a helical control grid 82. The control grid isprovided with an integral flat portion 33 held between the plates andwelded thereto. As clearly shown in Fig. 4, each grid 32 encompasses acorresponding filament l9 and is coaxial therewith. The controlelectrodes |5 are individually supported by metallic rods or wires 34seated in the end wall I2 of the enclosing vessel.

The control electrodes are each encompassed by a shield electrode which,as shown in Fig. 4, comprises a pair of parallel supporting Wires 35carrying a plurality of U-shaped wires 35 which are disposed parallel toone another and are secured to the wires 35 in any suitable manner, forexample, by welding. The supporting wires 35 are secured, as by welding,to a support or plate 31, which is disposed in an oversized aperture 38in another plate or disc 39, and which is secured to the plate or disc39 by two spaced double U-shaped brackets 40. The disc or plate 39extends to immediately adjacent the inner wall of the cylindricalportion [6 of the enclosing vessel and together with the wire grids 36forms an assembly which serves as a shield between the controlelectrodes I5 and the anodes I4 and hence segregates these electrodesand the leading-in conductors 34 and 28 therefor, respectively, so thatthe device may be operated efficiently at ultra-high frequencies.

Disposed between each shield electrode and anode is a suppressorelectrode which may be of the same general construction in part as theshield electrode. Each suppressor electrode comprises a U-shaped wireportion 43 extending through an aperture 51 in a plate or disc 44 andsecured to parallel Wires 45 which are secured in turn to the plate ordisc 44, corresponding of the apertures 57 and 38 being aligned. Theplate or disc 44 is equally spaced from the plate or disc 39 andcoextensive therewith and is supported by the wires or rods 23 and awire or rod 45 sealed in the end wall 12 of the enclosing vessel andeach carrying a flexible wire or stub 41 secured to the disc or plate44. The plates or discs 39 and 44 are maintained in spaced relationshipby a plurality of insulators 48 to which tabs 49 and 5G integral withthe plates or discs 39 and 44, respectively, are secured by bent wires5! and form a condenser coupling the shield and suppressor electrodes.

In order to prevent distortion of the plates or discs 39 and 44 by heatduring the evacuation treatment of the device and thereby to assureuniform and substantially fixed spacing of the discs or plates and hencea constant capacitance therebetween, the plates or discs are dished.Preferably, the discs or plates are dished to form portions of aspherical surface.

The disc or plate 44 is electrically connected to one end, preferablythe negative or grounded end of the filaments 59 by the flexible wiresor stubs 41 secured to the rods or supports 23 and 46. This disc orplate serves to increase the shielding between the control electrodes I5and the anodes l4 and the leading-in conductors 34 and 28, respectively,therefor.

In the fabrication of the device, the shield and suppressor gridstructures may be assembled as a unit exteriorly of the enclosingvessel. The suppressor grid units 43, 45 may be secured to the plate 44and this plate and plate 39 then secured in the desired spaced relationby the insulating members 48. Each of the screen grid units may then bepositioned approximately in uniform spaced relation to the correspondingsuppressor grid, and the brackets 40 welded to the disc 39. The screengrids may then be positioned accurately with respect to thecorresponding suppressor grid by flexing the brackets 49 whereby thesupports or plates 3'! and the screen grids carried thereby are shiftedto the desired position.

In order to assure a more complete shielding between the anodes and thecontrol grids and filaments, U-shaped imperforate strips 53 may beprovided at the ends of the suppressor grids, the strips 53 conformingin outline to the suppressor grid and being secured as by welding to thedisc 44.

As will be apparent, the cathodes 19 are supported separately from thediscs or plates 39 and 44 so that movement of the latter will not affectthe position of the cathodes with respect to the control grids and theanodes. Although the disc 44 is connected electrically to the cathodesby the wires ll, these wires preferably are so flexible in comparison tothe supports or rods 23 that movement of the disc 44 will not becommunicated to the cathodes.

A metallic disc 54 carrying a getter material 55 such as magnesium issupported by a short wire or stub 55 sealed in the end wall I l of theenclosing vessel at a point remote from the electrodes. After theelectrodes have been outgassed and the enclosing vessel sealed, thegetter may-be flashed,

as by high frequency induction heating, to fix residual gases within theenclosing vessel.

Although a specific embodiment of the invention has been shown anddescribed, it will be unmade therein Without departing from the scopeand spirit of this invention as defined in the appended claims.

What is claimed is:

30 derstood, of course, that modifications may be" 1. An electrodeassembly for electron discharge devices, comprising a plurality ofspaced discs, an electrode carried by one of said discs, anotherelectrode in juxtaposition to said first electrode, and means supportingsaid second electrode from another of said discs and separate from saidone disc, said means being laterally adjustable to align said anotherelectrode with said first electrode.

2. An electrode assembly for electron discharge devices comprising apair of discs, an electrode mounted upon one of said discs, anotherelectrode within said first electrode, and means mounting said anotherelectrode separate from said one disc including a member supporting saidsecond electrode from the other of said discs, said member beingflexible at right angles to the longitudinal axis of said electrodeswhereby said another electrode may be positioned accurately within saidfirst electrode.

- 3. An electrode assembly for electron discharge devices, comprising aplurality of discs, an electrode mounted on one of said discs, asupport, another electrode mounted solely on said support, and meanssecuring said support to another of said discs, said. means providingthe sole" mount for said support and being adjustable to center saidsecond electrode laterally with respect to said first electrode.

4. An electrode assembly for electron discharge devices, comprising aplurality of discs, an elecdevices, comprising a plurality of discshaving axially aligned apertures, an electrode mounted on one of saiddiscs and overlying an aperture therein, another electrode Within saidfirst electrode, a plate supporting said second electrode and disposedin the corresponding aperture in another of said discs, and flexiblebracket members securing said plate to said second disc.

6. An electrode assembly for electron discharge devices, comprising apair of spaced discs having axially aligned apertures, an electrodemounted upon one of said discs and overlying an aperture therein, asupport disposed adjacent the corresponding aperture in the other ofsaid discs, an electrode carried by said support and cooperativelydisposed with respect to said first electrode, and a flexible doubleU-shaped member securing said support to said other disc.

7. An electrode assembly for electron discharge devices, comprising apair of spaced discs having axially aligned apertures, a U-shaped gridelectrode mounted upon one of said discs and overlying an aperturetherein, another U-shaped grid electrode disposed within said first gridelectrode, and adjustable means supporting said second grid electrodefrom the other of said discs.

8. An electrode assembly for electron discharge devices, comprising apair of spaced discs having axially aligned apertures, a U-shaped gridmounted upon one of said discs and overlying an aperture therein, aplate member adjacent the corresponding aperture in the other of saiddiscs, another U-shaped grid mounted upon said plate member and disposedwithin said first grid, and a plurality of flexible double U-shapedmembers supporting said plate from said other disc.

JOSEPH P. LAICO.

